ENIGMA II

Once upon a time, an old man lived with his beautiful and clever daughter, Beth. The man had sadly lost his wife many years before, and had always been in charge of looking after her beloved daughter, whose beauty was well-known in the shire.


They had always had good harvest, with which they fed their cows and sheep and from which they got some money when they sold them in the market.


Unfortunaly, that year a terrible storm devastated their crops. However, the old farmer had some savings, which he used to buy food that winter for them and also to feed their animals. Both the farmer and Beth spent those months working as hard as they could so as to get good crops the following spring.


Although they expected an abundant harvest, a terrible storm destroyed the crops some days before harvesting them. There was nothing they could do except praying, because they had no money left, no savings, no food...


Unexpectedly, the marquis of the shire was walking that day round there, and he heard Beth crying. She told him what had happened, so he offered to help: he would give them the money they needed for the winter. Nevertheless, they would have to give him back double the amount he had lent them when they had harvested the following crops.


The following winter passed by and father and daughter worked harder and harder as the deadline came nearer, but it hadn't rained for several months, so they couldn't gather the money which had been lent to them months before. When spring came, the marquis of the shire arrived with some soldiers and asked for his money, having to admitt that they could not give it back to him.


The marquis got really angry, and promised to hang the farmer if he did not give him the money back. As a result, Beth started to cry and begged for his father. She told the marquis she would do anything, but she asked the marquis and his soldiers not to kill his father.


The marquis, which found the situation quite funny, decided to give another chance to those poor people, and said: "OK, let's bet on a new game. I won't kill your father as long as you play a game with me. This road is plenty of black and white stones. I will ask one of my soldiers to bring a black bag. Afterwards, I will put a black stone and a white stone inside it. Next, you will take one stone out of the bag: if the stone is white, your father will be free and you won't have to give me any money back. On the other hand, if you take the black stone, I will kill your father, I will keep your farm and you will have to marry me. Deal?".


Beth, who knew how powerful the marquis was, and knowing she had no other chance, agreed to do it. A soldier brought the black bag but... the marquis introduced two BLACK stones inside the bag!!! Beth knew she could not say what she had seen because the marquis would kill both her father and her; they could not run away either... However, Beth was the cleverest girl in the area, so she was able to solve the problem in a clever way without risking their lives...

How did she do it???